AB1669 CLINICAL, HISTOLOGICAL FEATURES AND PREDICTORS OF RELAPSE IN PATIENTS WITH IDIOPATHIC GRANULOMATOUS MASTITIS
Authors: B. Abbi, N. Sanghavi, S. Lanjewar, S. Fineberg, X. Xie, A. Gupta, A. Kumthekar, B. Ayesha
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Idiopathic Granulomatous mastitis (IGM) is a chronic benign inflammatory breast disease characterized by non-caseating granuloma with multinucleate giant cells and micro-abscesses[1]. It presents as painful breast lump, with axillary lymphadenopathy, nipple retraction, and peau d'orange appearance of the skin mimicking inflammatory breast cancer [1]. Till date, there are no consensus guidelines of managing IGM and it is increasingly being treated with steroids and steroid-sparing agents as it now considered to be driven by inflammatory process [2]. Since the relapse rate varies from 5-50% [3], identification of risk factors that predict relapse can help clinicians triage patients who might need close monitoring and prolonged treatment with immunosuppressive therapy. <h3>Objectives</h3> The objective of our study is to describe clinical, laboratory and histopathological features of IGM from a single center and identify distinguishing features of relapsing disease compared to remission. <h3>Methods</h3> We queried databases at our institution December 1990- January 2021 to include females ≥ 18 years with biopsy-proven diagnosis of IGM, excluding patients with breast cancer, lymphoproliferative disorders, solid organ malignancy, foreign body reaction in breast, plasma cell mastitis, and ductal ectasia. Remission was defined as three-month period without recurrence of symptoms or imaging findings. Relapse was defined as recurrence after three months of remission. Clinical and histopathological features were compared using two-sample t-tests (continuous variables) and chi-squared tests (categorical variables). <h3>Results</h3> 27 patients met our inclusion criteria and were included in the final analyses. The mean age at diagnosis was 35.8 years (± SD 9.4 years) with a mean body mass index of 31.7 kg/m2 (± SD 6.7 kg/m2). 11 (41%) were Hispanic, 25 (93%) had at least one previous full-term pregnancy prior to diagnosis and 8 (30%) were on oral contraceptives. 18 patients (66%) had remission and 9 (33%) had relapse. Six of these patients received steroid after antibiotics, while 5 patients were received methotrexate. Three (33%) patients with relapse and 14 (77%) with remission, had abscess formation confirmed on histopathology (p=0.04). <h3>Conclusion</h3> We did not identify any differences in clinical or laboratory features of patients with relapse and remission. Patients with remission had a higher number of abscesses on histopathology and history of oral contraceptive use was associated with more relapse. By identifying key histopathological findings in this population may guide prognosis and treatment of these patients. <h3>References</h3> [1]Altintoprak F. Aetiology of idiopathic granulomatous mastitis. Vol. 2, World Journal of Clinical Cases. 2014. p. 852. [2]Oran EŞ, Gürdal SÖ, Yankol Y, Öznur M, Calay Z, Tunaci M, et al. Management of idiopathic granulomatous mastitis diagnosed by core biopsy: A retrospective multicenter study. Breast J. 2013;19(4):411–8. [3]Sakurai K, Fujisaki S, Enomoto K, Amano S, Sugitani M. Evaluation of follow-up strategies for corticosteroid therapy of idiopathic granulomatous mastitis. Surg Today. 2011;41(3):333–7. <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> None Declared.